82 research outputs found

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    Sammanfattning Begreppet slöseri, av engelskans waste, Ă€r en term som i dagslĂ€get saknar en klar och entydig definition inom mjukvaruutveckling. Denna rapport har skrivits vid Kungliga Teniska Högskolan i Stockholm och syftar att klargöra termen slöseri och vad den innebĂ€r men hjĂ€lp av olika projektledningsverktyg frĂ„n IT-branchen. Det har framkommit att förtag sĂ€llan jobbar med en och endast en projektledningsmetod inom mjukvaruutveckling utan det blandas verktyg frĂ„n olika metoder. Det Ă€r ofta brist pĂ„ kunskap om valda verktyg och hur de ska anvĂ€ndas samt vilka olika verktyg som kompletterar varandra eller ej Ă€r kompatibla med varandra. En ökad medvetenhet kring valda modeller och verktyg skulle leda till ökad effektivitet och minskat slöseri. NĂ„got som Ă€r gemensamt för samtliga agila projektledningsmetoder Ă€r en strĂ€van efter att minska mĂ€ngden slöseri pĂ„ ett eller annat sĂ€tt och öka flödeseffektiviteten. Det Ă€r av stor vikt att lĂ€gga fokus pĂ„ rĂ€tt slöseri för att Ă„stadkomma största effektivisering dĂ„ olika slöserier pĂ„verkar olika mycket. Det finns ingen uttalad efterfrĂ„gan frĂ„n nĂ€ringslivet pĂ„ en definition av termen slöseri utan den engelska termen “waste” anvĂ€nds, Ă€ven pĂ„ svenska. En potentiell definition för termen slöseri skulle kunna vara - nĂ„got som Ă€r i vĂ€gen eller hindrar effektivt arbete med pĂ„gĂ„ende projekt. Denna rapport behandlar endast slöseri ur en projektledares eller produktĂ€gares perspektiv inom mjukvaruutveckling, ej drift av IT-system.Abstract The concept of “slöseri”, from the English word waste, is a term that lacks a clear and unambiguous definition. This report has been written at the Royal Institute of Technology in Stockholm and aims to clarify the term “slöseri” and what it means by using various project management tools from the IT-industry. It has emerged that companies rarely work with one and only one project management method in software development, they rather mix tools from different methods. There is often a lack of knowledge about the selected tools and how to use them and which tools that complement each other and which are not compatible with each other. An increased awareness on selected models and tools would lead to increased efficiency and reduced “slöseri”. Something that is common to all agile project management methodologies is a desire to reduce the amount of waste in one way or another and increase flow efficiency. It is very important to focus on the right waste to achieve maximum efficiency du to that different types of waste affects to varying degrees. There is no explicit demand from the business community on a definition of “slöseri” because the term waste is used, even in Swedish. A potential definition for the term waste could be - something that’s in the way or hinder effective work on current projects. This report deals only with waste from a project manager or product owner’s perspective in software development, not the operation of IT-systems

    Disk formation and the origin of clumpy galaxies at high redshift

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    Observations of high redshift galaxies have revealed a multitude of large clumpy rapidly star-forming galaxies. Their formation scenario and their link to present day spirals is still unknown. In this Letter we perform adaptive mesh refinement simulations of disk formation in a cosmological context that are unrivalled in terms of mass and spatial resolution. We find that the so called "chain-galaxies" and "clump-clusters" are a natural outcome of early epochs of enhanced gas accretion from cold dense streams as well as tidally and ram-pressured stripped material from minor mergers and satellites. Through interaction with the hot halo gas, this freshly accreted cold gas settles into a large disk-like system, not necessarily aligned to an older stellar component, that undergoes fragmentation and subsequent star formation, forming large clumps in the mass range 10^7-10^9 M_sun. Galaxy formation is a complex process at this important epoch when most of the central baryons are being acquired through a range of different mechanisms - we highlight that a rapid mass loading epoch is required to fuel the fragmentation taking place in the massive arms in the outskirts of extended disks, an accretion mode that occurs naturally in the hierarchical assembly process at early epochs.Comment: Minor revision of the text, accepted for publication in MNRAS Letters. A version with high-resolution figures can be found at http://www-theorie.physik.unizh.ch/~agertz/CLUMP

    The formation of disc galaxies in a LCDM universe

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    We study the formation of disc galaxies in a fully cosmological framework using adaptive mesh refinement simulations. We perform an extensive parameter study of the main subgrid processes that control how gas is converted into stars and the coupled effect of supernovae feedback. We argue that previous attempts to form disc galaxies have been unsuccessful because of the universal adoption of strong feedback combined with high star formation efficiencies. Unless extreme amounts of energy are injected into the interstellar medium during supernovae events, these star formation parameters result in bulge dominated S0/Sa galaxies as star formation is too efficient at z~3. We show that a low efficiency of star-formation more closely models the subparsec physical processes, especially at high redshift. We highlight the successful formation of extended disc galaxies with scale lengths r_d=4-5 kpc, flat rotation curves and bulge to disc ratios of B/D~1/4. Not only do we resolve the formation of a Milky Way-like spiral galaxy, we also observe the secular evolution of the disc as it forms a pseudo-bulge. The disc properties agree well with observations and are compatible with the photometric and baryonic Tully-Fisher relations, the Kennicutt-Schmidt relation and the observed angular momentum content of spiral galaxies. We conclude that underlying small-scale star formation physics plays a larger role than previously considered in simulations of galaxy formation.Comment: Published in MNRA

    QTL linkage analysis of connected populations using ancestral marker and pedigree information

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    The common assumption in quantitative trait locus (QTL) linkage mapping studies that parents of multiple connected populations are unrelated is unrealistic for many plant breeding programs. We remove this assumption and propose a Bayesian approach that clusters the alleles of the parents of the current mapping populations from locus-specific identity by descent (IBD) matrices that capture ancestral marker and pedigree information. Moreover, we demonstrate how the parental IBD data can be incorporated into a QTL linkage analysis framework by using two approaches: a Threshold IBD model (TIBD) and a Latent Ancestral Allele Model (LAAM). The TIBD and LAAM models are empirically tested via numerical simulation based on the structure of a commercial maize breeding program. The simulations included a pilot dataset with closely linked QTL on a single linkage group and 100 replicated datasets with five linkage groups harboring four unlinked QTL. The simulation results show that including parental IBD data (similarly for TIBD and LAAM) significantly improves the power and particularly accuracy of QTL mapping, e.g., position, effect size and individuals’ genotype probability without significantly increasing computational demand

    Community-associated Methicillin-resistant Staphylococcus aureus Bacteremia and Endocarditis among HIV Patients: A cohort study

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    <p>Abstract</p> <p>Background</p> <p>HIV patients are at increased risk of development of infections and infection-associated poor health outcomes. We aimed to 1) assess the prevalence of USA300 community-associated methicillin-resistant <it>Staphylococcus aureus </it>(CA-MRSA) among HIV-infected patients with <it>S. aureus </it>bloodstream infections and. 2) determine risk factors for infective endocarditis and in-hospital mortality among patients in this population.</p> <p>Methods</p> <p>All adult HIV-infected patients with documented <it>S. aureus </it>bacteremia admitted to the University of Maryland Medical Center between January 1, 2003 and December 31, 2005 were included. CA-MRSA was defined as a USA300 MRSA isolate with the MBQBLO spa-type motif and positive for both the arginine catabolic mobile element and Panton-Valentin Leukocidin. Risk factors for <it>S. aureus</it>-associated infective endocarditis and mortality were determined using logistic regression to calculate odds ratios (OR) and 95% confidence intervals (CI). Potential risk factors included demographic variables, comorbid illnesses, and intravenous drug use.</p> <p>Results</p> <p>Among 131 episodes of <it>S. aureus </it>bacteremia, 85 (66%) were MRSA of which 47 (54%) were CA-MRSA. Sixty-three patients (48%) developed endocarditis and 10 patients (8%) died in the hospital on the index admission Patients with CA-MRSA were significantly more likely to develop endocarditis (OR = 2.73, 95% CI = 1.30, 5.71). No other variables including comorbid conditions, current receipt of antiretroviral therapy, pre-culture severity of illness, or CD4 count were significantly associated with endocarditis and none were associated with in-hospital mortality.</p> <p>Conclusions</p> <p>CA-MRSA was significantly associated with an increased incidence of endocarditis in this cohort of HIV patients with MRSA bacteremia. In populations such as these, in which the prevalence of intravenous drug use and probability of endocarditis are both high, efforts must be made for early detection, which may improve treatment outcomes.</p

    Lysine harvesting is an antioxidant strategy and triggers underground polyamine metabolism

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    Both single and multicellular organisms depend on anti-stress mechanisms that enable them to deal with sudden changes in the environment, including exposure to heat and oxidants. Central to the stress response are dynamic changes in metabolism, such as the transition from the glycolysis to the pentose phosphate pathway—a conserved first-line response to oxidative insults1,2. Here we report a second metabolic adaptation that protects microbial cells in stress situations. The role of the yeast polyamine transporter Tpo1p3,4,5 in maintaining oxidant resistance is unknown6. However, a proteomic time-course experiment suggests a link to lysine metabolism. We reveal a connection between polyamine and lysine metabolism during stress situations, in the form of a promiscuous enzymatic reaction in which the first enzyme of the polyamine pathway, Spe1p, decarboxylates lysine and forms an alternative polyamine, cadaverine. The reaction proceeds in the presence of extracellular lysine, which is taken up by cells to reach concentrations up to one hundred times higher than those required for growth. Such extensive harvest is not observed for the other amino acids, is dependent on the polyamine pathway and triggers a reprogramming of redox metabolism. As a result, NADPH—which would otherwise be required for lysine biosynthesis—is channelled into glutathione metabolism, leading to a large increase in glutathione concentrations, lower levels of reactive oxygen species and increased oxidant tolerance. Our results show that nutrient uptake occurs not only to enable cell growth, but when the nutrient availability is favourable it also enables cells to reconfigure their metabolism to preventatively mount stress protection

    First finds of Prunus domestica L. in Italy from the Phoenician and Punic periods (6th-2nd centuries BC)

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    Abstract During the archaeological excavations in the Phoenician and Punic settlement of Santa Giusta (Oristano, Sardinia, Italy), dating back to the 6th–2nd centuries bc, several Prunus fruitstones (endocarps) inside amphorae were recovered. The exceptional state of preservation of the waterlogged remains allowed morphometric measurements to be done by image analysis and statistical comparisons made with modern cultivated and wild Prunus samples collected in Sardinia. Digital images of modern and archaeological Prunus fruitstones were acquired with a flatbed scanner and analysed by applying image analysis techniques to measure 26 morphometric features. By applying stepwise linear discriminant analysis, a morphometric comparison was made between the archaeological fruitstones of Prunus and the modern ones collected in Sardinia. These analyses allowed identification of 53 archaeological fruitstones as P. spinosa and 11 as P. domestica. Moreover, the archaeological samples of P. spinosa showed morphometric similarities in 92.5% of the cases with the modern P. spinosa samples currently growing near the Phoenician and Punic site. Likewise, the archaeological fruitstones identified as P. domestica showed similarities with the modern variety of P. domestica called Sanguigna di Bosa which is currently cultivated near the village of Bosa. Currently, these findings represent the first evidence of P. domestica in Italy during the Phoenician and Punic periods. Keywords Archaeobotany · Image analysis · Morphometric features · Prunus · Sardini
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